The present invention relates to an image recording apparatus which uses an elongated photosensitive recording medium, and more particularly, to such apparatus provided with a reversal sheet feeding device and control means for starting an image recording operation in connection with the reversal feeding of the recording medium.
Known is a photosensitive image recording medium including a photosensitive pressure sensitive recording medium and a developer medium. The photosensitive pressure sensitive recording medium comprises a microcapsule sheet whose microcapsules encapsulate therein chromogenic material or dye precursor, and the developer medium includes a substrate and developer material layer coated thereover. Such image recording medium is disclosed for example in U.S. Pat. No. 4,399,209.
In one conventional image recording apparatus, transfer type image recording operation has been achieved. That is, the microcapsule sheet is subjected to an image light exposure for selectively changing physical property of the microcapsules dependent on the light exposure, to thereby form a latent image. Then, the light exposed microcapsule sheet is superposed with the developer medium and the two sheets are pressed together, so that the chromogenic material are selectively reacted with the developer material to provide an output image on the developer sheet.
To achieve the above operation, the elongated microcapsule sheet passes through its sheet path extending through, in order, an exposure stand, a pressure developing unit, and a thermal fixing unit. In one image recording or copying operation, a given length of the microcapsule sheet is required. In this case, as shown in FIG. 1(a) the light exposed zone E of the microcapsule sheet M is delivered to the pressure developing unit and at the same time, the subsequent green zone G of the microcapsule sheet (entirely unexposed zone) is also passed through the exposure stand. If the next exposure operation for the next image recording operation is started with a subsequent zone S, the green zone G is disadvantageously wasted. As a result, copying cost increased if great numbers of copying operation is repeatedly carried out.
To avoid this problem, after the pressure developing operation with respect to the precedent exposure zone E, the microcapsule sheet M is reversely fed toward a microcapsule sheet supply side such as toward a sheet cartridge so as to start the next copying operation with a minimized length of the green zone G' as shown in FIG. (b). Such reversal sheet feeding is provided by reversely rotating the sheet cartridge for rewinding the microcapusle sheet therein.
In the conventional image recording apparatus having the reversal sheet feeding system, even if urgent copying operation is required at the time of the reversal sheet feeding period, for example even if an operator depresses a copy start key during the reversal sheet feeding period, the intended copying cannot be started until the reversal sheet feeding operation is completed. Therefore, the operator must again manipulate or depress the copy start key after the completion of the reversal sheet feed. Such manipulation would be troublesome and time consuming.
Incidentally, reversal sheet feeding means is disclosed in U.S. Pat. Nos. 4,819,024 and 4,801,976.